[Stephen De vere]

Rafael,

I first graded the film with 3-way CC (and some others of course). It took me weeks to complete. Then to my absolute horror I noticed the bit-truncation apparent in the histogram, a tool I only opened by chance (I only ever histogram in stills cameras because there is nothing else). I then started to do the whole job over again using the 1-way CC to replace the 3-way corrections. Now it seems the 3-way CC in fact is fine

I hope you are not suggesting that the one-way CC filter is 8b RGB only and it should not be used in my 10-bit timeline ?

[Stephen De vere]

I see now that filters is the only way to hope to achieve Broadcast Safe master, and that all the scopes windows are just rough guide.

I plan now to put Broadcast Safe filter and a Levels filter to remove sub-blacks, hoping the apparent truncating of bits is not for real on final output.

[Stephen De vere]

Thanks Rafael I think you have got me onto the right track to solve this – I did an export/import test, (remembering not to use Quicktime Conversion which is well known to be buggy also) and the truncating problem showing in scopes is removed.

So it is some aspect of the still frame render preview. I will look at all those settings too.

I guess I must export the 53 minutes self-contained and then re-import to play out to tape.

Is there a list of ‘gotchas’ anywhere on the www ?

[Stephen De vere]

By playing around I’ve narrowed the problem down within the Broadcast Safe filter to the ‘Saturation Limiting’ control.

‘Luminance Limiting’ seems to not have the effect.

Also tried changing sequence codec to 8-bit UC, but same results.

I can now notice the gaps are in the waveform graph too, when applying these apparently damaging filters.

Are you able to reproduce this effect in your setup Rafael ?

[Stephen De vere]

Yes.
Shot and captured full res DVCPro50
Apple 10-bit UC sequence (just now for the finishing)
Render in 10-bit high YUV

I just tried switching to Blackmagic 10-bit UC but same result.

I also downloaded the free Grading Sweet Legalise filter, but it won’t run (FXScript Error) – must be not compatible with my FCP 4.5

[Stephen De vere]

Rafeal,

So the bit-trunkating (severe ‘combing’) I see in the Histogram, caused by the 3-way CC and B’Safe filters, I should not worry about ? That would be extremely difficult to accept.

I have to say I cannot see the loss in the broadcast monitor.

Beginning to feel I wish I went back to Avid – even the low end version handles this so much more professionally. Their BSafe filter gives control of Composite in addition to Chroma, Luma, RGB.

[Stephen De vere]

Walter,
“In my experience, that’s a false reading on the FCP Scopes after render. The FCP scopes would show some video levels over 100 after render, but our shows never failed QC so I know that’s a false reading. ”

So the FCP scopes are fundamentally flawed and ought not be used for broadcast work ?

I thought the sampling rate had improved in later FCP releases but perhaps still not enough – maybe just too processor intensive even in still mode to measure every pixel ?

[Stephen De vere]

I also find that Broadcast Safe filter truncates the bits in the entire image – so worried I lose quality (the source camera files are 8-bit DVCPro50 but I am using a 10-bit uncompressed timeline for the finishing). The same happens with the 3-way Color Corrector but the 1-way Color Corrector filter is fine so I am using that.

Is there anywhere on the net a history/list of FCP versions and their problems and the plugins available to fix ?

OK, sorry, I just found a recent post on this subject
“Does (Broadcast Safe) filter order matter?” that goes into it all.

[Stephen De vere]

Rafael,

Thanks for your reply.

It seems the Broadcast Safe filter is the only tool that might ensure legal levels (assuming it is given correct settings) but I had read that it is not reliable – that it gives different results before and after full timeline rendering.

I prefer manual control and I was hoping to achieve safe levels shot-by-shot using the vectorscope and waveform windows.

So really, only professional external hardware will do a proper legal levels job ?

IS FCP 7 any more ‘mature’ in this respect ?

[Stephen De vere]

CCEMP does sound very cool for the price.

Andrius, Eric,

You’ve both been incredibly helpful – thank you. I am in contact with a studio in London now that have done some major DVD titles and it looks like I can afford them. Armed with your excellent knowledge I’ve been able to ask the pertinent questions and they’ve held up so far.

If it doesn’t work out I’ll get in touch – if I had a little more time and leaway with the schedule I would have taken you up on the offers, thanks. Maybe next time.